Eczema can occur anywhere on the body but it is common on the backs of the knees. This is due to areas of skin rubbing against each other and moisture forming in the skin creases.
Eczema is a medical term for conditions that cause itchy and dry patches of skin.
The most common type of eczema is atopic dermatitis. It is a chronic inflammatory skin condition in approximately 9.6 million children and about 16.5 million adults in the United States.
Atopic dermatitis usually affects the following areas:
- insides of the elbows
- backs of the knees
This article reviews eczema on the backs of knees, symptoms, possible complications, causes, diagnosis treatments, prevention, and outlook.
Symptoms can vary depending on if eczema is mild or severe.
People with mild eczema may experience dry patches, and the itchiness may come and go in their creases. In more severe cases, atopic eczema can cause widespread inflammation, more intense itching, and swelling.
Atopic dermatitis rashes may cause the following:
- areas that ooze or weep fluid
- bleeding when scratched, making skin vulnerable to infection
- dry and discolored areas, causing thickening and hardening known as lichenification
The affected areas may become red on lighter skin and purple, brown, or gray on darker skin tones.
Scratching can disrupt sleep which may lead to the following:
- sleepless nights
- difficulty concentrating at school or work
- inability to perform daily activities
A skin infection may appear similar to eczema itself, so a person should look for signs of the following and seek medical attention:
- yellowish-orange crusts forming on top of eczema patches
- pus-filled blisters on top of eczema
- cold sores, or fever blisters
- reddish, swollen bumps on the skin
- streaks or redness spreading on the skin
A parent or caregiver may also notice their child has the following:
Eczema often occurs in the creases of the skin behind the knees and other areas of skin that rub against each other or are easy to scratch, which leads to irritation. For babies, this may result from crawling. For toddlers or adults, it may result from walking.
Atopic dermatitis typically begins in childhood, usually in the first 6 months of life. Some children’s symptoms may become milder as they grow, while others will experience flares into adulthood. In other cases, adults may experience adult-onset eczema.
The exact cause of atopic eczema remains unclear. Eczema often occurs in people who have other allergies. “Atopic” means sensitivity to allergens.
The protein filaggrin is essential to developing and maintaining the skin barrier. Research from 2015 shows that mutations in the FLG gene, which encodes filaggrin, increase the risk of atopic dermatitis.
Eczema may be a combination of having an inherited tendency to it and exposure to environmental triggers.
Many common household items are potential environmental irritants that can lead to an eczema flare. Triggers of eczema on the backs of knees include:
- extended exposure to extreme temperatures, resulting in sweat forming on the backs of the knees
- certain types of soaps, such as bubble bath products or body wash
- certain chemicals in:
- laundry detergents and fabric softeners
- leather dyes, such as on a sofa
- antibacterial products, such as wipes
- surface cleaners and disinfectants if they make contact with the skin
- certain fabrics, such as wool or polyester, in trousers and sheets
- dust mites
Exercise may also cause a flare due to the sweat that may form in the creases.
Doctors will usually be able to diagnose atopic eczema by examining a person’s skin symptoms and asking questions about their frequency and the effect on their quality of life.
Doctors will estimate the area of involvement across four body regions:
- head and neck
- upper extremities — arms
- lower extremities — legs, including the backs of legs
They assign it an area score:
- 1 (1–9%)
- 2 (10–29%)
- 3 (30–49%)
- 4 (50–69%)
- 5 (70–89%)
- 6 (90–100%)
Next, doctors assess each region for four signs:
- erythema — skin reddening
- edema — skin swelling
- excoriation — skin picking
- lichenification — skin swelling
Doctors will assign each region multiplier that reflects the area in relation to the total body surface area.
The final EASI score is the summation of the 4 regional scores, ranging from 0–72.
There is no cure for eczema, but there are methods to relieve symptoms that doctors will include in a personalized treatment plan.
Depending on a person’s age and the severity of eczema on the backs of their knees, treatment may include:
- moisturizing creams, emollients, or lotions for dry skin behind the knees
- topical corticosteroids
- over-the-counter anti-itch creams
Doctors may also prescribe the following medications:
- creams, including topical corticosteroids to reduce swelling and redness, which are also suitable for children and pregnant people
- topical or oral Janus Kinase-Signal transducer inhibitors
- topical calcineurin inhibitors, which are nonsteroidal medications available as creams and ointments
- topical phosphodiesterase 4 (PDE4) inhibitors, which come in ointments
- oral immunosuppressants
- biologic injections, in more severe cases for children over 6 years and adults
- systemic medications
- light therapy, in moderate to severe cases
Management and preventions
If atopic dermatitis is mild, management may include:
- avoiding triggers
- maintaining a regular bathing and moisturizing routine to protect and strengthen the skin barrier
- getting sufficient sleep
- eating a balanced diet
- managing stress
Many people with eczema also benefit from alternative treatments, including:
- diluted bleach baths, with parental supervision if necessary
- oatmeal baths
- medical-grade honey, such as Manuka honey
An adult, parent, or caregiver should consult a medical professional before starting any natural treatments.
Eczema commonly occurs in the creases on the body, including the backs of the knees. Atopic dermatitis is the type that tends to affect more people, causing itching, dryness, and skin discoloration.
Both children and adults can develop eczema behind their knees or on other joint areas. Treatment plans include moisturizers, topical medications, and other methods such as wet wraps and managing triggers.
A person may also benefit from alternative therapies such as medicated baths and acupuncture.